Laser light irradiator

ABSTRACT

A laser beam irradiation device according to the present invention is so constructed that it may increase or decrease the excitation electric current flowing through its semiconductor laser diode to enable a user to selectively practice both non-thermal and photo-thermal laser treatments.  
     CPU  41  is responsive to switching-on and -off of an output-power switching unit S 2  for sending a reference signal to an amplifier  472  via an I/O port  44  and a D/A converter  471 , so that the amplifier  472  may provide at its output terminals a reference voltage, with respect to which a control reference voltage for a desired laser output can be determined.  
     Semiconductor laser diode  35  radiates the laser beam from its opposite sides, and a photo-diode  473  receives one of the opposite laser beams to provide a light-accepting voltage at its output terminals. The so acquired light-accepting voltage is directed to an amplifier  474  for amplification, thereby obtaining the monitor voltage.  
     The reference voltage and the monitor voltage are applied to a differential amplifier  475 , and a differential voltage is amplified by an amplifier  476 . Thus a controlled working electric current is made to flow in semiconductor laser diode  35  so that it may be energized and oscillated at the set output level.

TECHNICAL FIELD

[0001] The present invention relates to a laser beam irradiation devicefor projecting a laser beam to one's skin for beauty treatments such asskin treatment, removal of undesired hair and suchlike to make personsmore beautiful.

BACKGROUND ART

[0002] When human skin is exposed to a laser beam under the skintemperature of 36 centigrade, on the skin caused is a certain vitalreaction, which is called “non-thermal reaction”. It includesphotoelectric effect, photo-magneto effect, photo-dynamics effect,photochemical effect, photo-immunization effect, photo-zymogenesiseffect and other such like optical effects.

[0003] Such non-thermal reactions are applied to body treatments such asslimming and hair restoration, since they stimulate blood circulation,body metabolism and the likes.

[0004] Also, when the skin is exposed to a laser beam, Joule heat iscaused in the skin tissue by photothermal reaction to raise thetemperature of the skin tissue.

[0005] The rise of the skin temperature causes various reactions suchas; flashing, protein transformation, blood clot, vaporization, andcarbonisation.

[0006] Such photothermal reactions are applied to beauty treatments suchas: a skin beauty treatment, in which birth marks, stains, freckles andother unpleasing pigment cells are reduced into minute particles almostunnoticeable; and a depilation treatment, in which proteintransformation is caused in hair root cells to destroy the regenerationmechanism of human hair.

[0007] These non-thermal and photothermal reactions can be selectivelycaused, depending on how much energy density a used laser beam has.

[0008] Referring to FIG. 7, a semiconductor laser diode is responsive toapplication of voltage for starting an electric current to flow, and atthe outset it radiates natural light. A laser oscillation is caused whenthe so started electric current rises beyond a certain threshold value,and the laser output drastically increases in proportion to theincreasing electric current, and accordingly the energy density of thelaser beam increases.

[0009] The object of the present invention is to provide a laser beamirradiation device capable of giving both the non-thermal andphotothermal treatments by controlling the amount of electric currentexcited in its semiconductor laser diode to adjust output power of thelaser beam.

SUMMARY OF THE INVENTION

[0010] To attain this object a laser beam irradiation device accordingto the present invention, specifically as defined in claim 1 comprises:

[0011] a semiconductor laser diode for producing a laser beam;

[0012] a switching means for changing the semiconductor laser diode inoperation from one to another outputting state or vice versa; and

[0013] a control circuit for controlling the amount of working currentflowing in the semiconductor laser diode to adjust output power of thelaser beam by using the switching means.

[0014] The laser beam irradiation device according to claim 2 is adevice as defined in claim 1, whose switching means is adapted to changethe semiconductor laser diode between high-outputting state andlow-outputting state.

[0015] The laser beam irradiation device according to claim 3 is adevice as defined in claim 1, whose control circuit functions to makethe working electric current flows and stops in the semiconductor laserdiode at regular intervals, thereby projecting the laser beamintermittently.

[0016] The laser beam irradiation device according to claim 4 is adevice as defined in claim 3, of which one shot of the intermittentradiation can be controlled in terms of rotation angle of a rotarycontrol.

BRIEF DESCRIPTION OF DRAWINGS

[0017]FIG. 1 is a perspective view of a laser beam irradiation deviceaccording to the present invention;

[0018]FIG. 2 is a front view of the console panel of the laser beamirradiation device;

[0019]FIG. 3 is a front view of the hand-held applicator;

[0020]FIG. 4 is a side view of the hand-held applicator, partly insection;

[0021]FIG. 5 is a block diagram of the control circuit;

[0022]FIG. 6 is a block diagram of the drive circuit; and

[0023]FIG. 7 is an excitation current-versus-laser output graph.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0024] The present invention is described below in respect of preferredembodiments.

[0025]FIG. 1 shows how it looks in appearance.

[0026] The laser beam irradiation device comprises a major body 10 andan associated hand-held applicator 30 connected to the major body 10 viaa given length of cable 20.

[0027] The major body 10 contains a control circuit 40, and the housingof the major body 10 has a recessed compartment 50 for accommodating thehand-held applicator 30 and a console 60 on its top surface, and a lid70 hinged to one side of the housing.

[0028]FIG. 2 shows the console.

[0029] On the console 60 arranged are a power switch S1, an output-powerswitching unit S2, a standby switch S3 and a rotary radiation controlV1, and further arranged are a power indicator LED L1 next to the powerswitch S1, a low-power indicator LED L21 and a high-power indicator LEDL22 next to the output-power switching unit, and a standby indicator LEDL3 next to the standby switch S3.

[0030] The power switch S1 functions to turn the power supply on and off(or put in or out of circuit), and accordingly the power indicator lampL1 turns on and off respectively.

[0031] The output-power switching unit S2 functions to make the laserchange in operation from a relatively low outputting state (for example1.0 watt) to a relatively high outputting state (for example 1.6 watts)or vice versa.

[0032] Then, the low power indicator LED L21 turns on for the relativelylow outputting state and turns off for the relatively high outputtingstate, whereas the high-power indicator LED L22 turns off for therelatively low outputting state and turns on for the relatively highoutputting state.

[0033] The output-power switching unit S2 can work only when the standbyswitch S3 is off.

[0034] The initial output power of the laser beam is automatically setat the relatively low outputting state Lo in response to the turning-onof the power switch S1.

[0035] When the standby switch S3 is turned on, the laser is set on astandby condition for radiation and the standby indicator LED L3 turnson. When the standby switch S3 is turned off, the standby condition ofthe laser is cancelled and the standby indicator LED L3 turns off.

[0036] The mere switching-on of the power switch S1 keeps the laser stayin non-standby condition.

[0037] When the standby switch S3 is turned on, an associated timerstarts counting to automatically turn off the standby switch S3 after apredetermined period (for example, 20 minutes) has passed irrespectiveof whether or not the laser has been radiated.

[0038] The rotary radiation control V1 is used to set a duration or doseof a single shot in the intermittent radiation in terms of its rotationangle, and the duration can change for example from one to nine seconds.

[0039] The rotary radiation control V1 can be operated to set a desiredduration of each shot even if the standby switch S3 is on. The initialradiation dose when the power switch S1 is turned on is determined bythe rotation angle of the rotary radiation control V1. The shot-to-shotinterval in the intermittent radiation is determined (for example, 1.5seconds) beforehand.

[0040] Referring to FIGS. 3 and 4, the hand-held applicator 30 has aface H projecting laterally from its top, and a push button switch S4 onits side.

[0041] Also, the hand-held applicator has vent holes “a” and “b” at thelower part and on the rear side of the face H.

[0042] The face H has a spherical lens 31 press-fitted in its centerhole, and the face H has a hollow cylinder 32 integrally connected toits circumference, encircling the spherical lens 31. The hand-heldapplicator 30 is applied to one's skin by the hollow cylinder 32 at itsedge.

[0043] A coaxial cylindrical electrode 33 is embedded in the hollowcylinder 32 to project forward therefrom at its open edge.

[0044] A heat sink 34 is placed behind the spherical lens 31, and asemiconductor laser diode 35 is press-fitted in a through-hole bored inthe center of the heat sink 34.

[0045] A cooling fan 36 is placed behind the heat sink 34.

[0046] The laser beam from the semiconductor laser diode 35 focuses onthe focal point of the spherical lens 31 in the focal plane, in whichthe opening of the hollow cylinder 32 lies. The focal length of thespherical lens 31 is short enough to converge all the light energy to alimited spot, allowing the so converged beam to diverge beyond the focalpoint with the result that the light energy is distributed over theextensive area.

[0047] Accordingly the light energy density drastically decreases withthe distance from the focal point, and therefore, there is little or nofear of injuring a living body even if it is exposed to the so dispersedlight beam.

[0048] The heat sink 34 allows the heat generated by the semiconductorlaser diode 35 to transmit therethrough. Thus, the semiconductor laserdiode 35 is prevented from lowering its output.

[0049] The heat sink 34 is made of aluminum or aluminum alloy, whosethermal conduction is relatively high, and the heat sink 34 has furtherthrough holes made therein to effectively improve its heat radiation.

[0050] The semiconductor laser diode 35 may be a PN junction diode ofGaAs or any other compound semiconductor, which can be excited by makingan electric current flow therethrough for laser oscillation.

[0051] The peak-to-peak wavelength of the semiconductor laser diode is600 to 1600 nm long, and the laser output ranged from 5 mW to 3W,thereby efficiently causing a sufficient photothermal reaction on theskin.

[0052] Further caused are additional optical effects other than therequired photothermal reaction, such as photoelectric effect,photo-magneto effect, photo-dynamics effect, photochemical effect,photo-immunizing effect, photo-zymogenesis effect and the like. Thephoto-biological activation expedites the body's metabolism and bloodcirculation under the skin. The laser beam is hardly absorbed by thewater contents and blood, and therefore, it can reach deep under theskin.

[0053]FIG. 5 shows the control circuit of the laser beam irradiationdevice.

[0054] It comprises: a CPU 41 having a memory 42 and a timer circuit 43both built therein; an output-power switching unit S2, a standby switchS3, a push button switch S4, a rotation angle detector 45 fordetermining the instantaneous rotation angle of the rotary radiationcontrol V1, and a touch sensor circuit 46 for detecting the touching ofthe electrode 33 on the skin, all of which are connected on the inputside of an I/O port 44; and a drive circuit 47 connected on the outputside of the I/O port 44 for controlling the working current in thesemiconductor laser diode 35.

[0055] The touch sensor circuit 46 comprises a high-frequency oscillatorcircuit and a switching circuit responsive to the working or non-workingof the oscillator for turning on or off.

[0056] The electrode 33 is connected to one terminal of an oscillationcoil of the oscillator circuit, and the oscillation stops as theelectrode 33 touches the skin. The switching circuit is responsive tothe stop of the oscillation for turning off.

[0057] The touch sensor circuit 46 may include an impedance element suchas a capacitance or a resistance whose impedance drastically varies inresponse to the touching of the electrode to the skin, or may include aswitching element or a piezoelectric element responsive to the touchingof the electrode to the skin.

[0058]FIG. 6 shows a block diagram of the drive circuit 47.

[0059] The CPU 41 is responsive to the switching-on and -off of theoutput-power switching unit S2 for sending a reference signal to anamplifier 472 via the I/O port 44 and a D/A converter 471, so that theamplifier 472 provides at its output terminal a reference voltage, withrespect to which a control reference voltage for a desired laser outputis determined.

[0060] The semiconductor laser diode 35 radiates the laser beam from itsopposite sides, and a photo-diode 473 receives one of the opposite laserbeams to provide a light-accepting voltage at its output terminals. Theso acquired light-accepting voltage is directed to the amplifier 474 foramplification, thereby obtaining the monitor voltage.

[0061] The reference voltage and the monitor voltage are applied to adifferential amplifier 475, and a differential voltage is amplified byan amplifier 476. Thus a controlled working electric current is made toflow in the semiconductor laser diode 35 so that it may be energized andoscillated at the set output level.

[0062] The semiconductor laser diode can be thus switched to therelatively high- or low-powered oscillation Lo or Hi.

[0063] The CPU 41 carries out the on-and-off control of the workingcurrent from the drive circuit 47 under the control of the timer circuit43.

[0064] The timer control includes two different modes, that is, thetreatment time control in which the working current is made to flow apredetermined length of time for each treatment, and the radiation dosecontrol in which the working current is made to flow a predeterminelength of time for each shot in the intermittent radiation.

[0065] The duration of a single shot in the intermittent radiation canbe set terms of the rotation angle of the rotary radiation control V1.

[0066] In carrying out a required beauty treatment with the soconstructed laser beam irradiation device of the present invention,first the power switch S1 is turned on.

[0067] Then, the output-power switching unit S2 is turned on to selecteither the relatively low outputting state Lo for the non-thermaltreatment or the relatively high outputting state Hi for thephotothermal treatment.

[0068] Next, the rotary radiation control V1 is rotated to set theduration of a single shot in the intermittent radiation.

[0069] Next, the standby switch S3 turns on to put the device in thestandby condition.

[0070] The hand-held applicator 30 is held in hand with the face Hdirected towards a selected spot on the skin at the angle of 90 degreesrelative to the skin, and then, the electrode 33 of the cylinder 32 ispushed against the selected spot.

[0071] Then, the push button switch S4 is depressed to turn thesemiconductor laser diode 35 on for predetermined seconds, and thenturns off for prescribed seconds.

[0072] The semiconductor laser diode 35 turns on or off alternately,projecting onto the spot the laser beam of the required strength Lo orHi, which is selected by the output-power switching unit S2.

[0073] A required beauty treatment is repeated as many times as requiredwhile moving the electrode 33 of the hand-held applicator 30 from placeto place on the skin.

[0074] The radiation of the laser beam is made to stop in response tothe electrode 33 being taken off from the skin, and the radiation of thelaser beam is made to start in response to the electrode 33 being put onthe skin.

[0075] Assuming that a fixed length of time has passed since theturning-on of the standby switch S3, it automatically turns off, therebystopping the radiation of the laser beam.

INDUSTRIAL APPLICABILITY

[0076] As described above, the laser beam irradiation device of thepresent invention is responsive to the selection of the beauty treatmentmodes for appropriately increasing or decreasing the working electriccurrent in the semiconductor laser diode. For that purpose, theoutput-power switching unit is designed to be selectively turned towardrelatively high outputting state for photothermal treatment and towardrelatively low outputting state for non-thermal treatment. Thisarrangement permits a safe and efficient beauty treatment as well as anexpansion of the applicable scope of the laser beam irradiation device.

[0077] Radiation of the laser beam is intermitted at a fixed interval bycontrolling the working electric current in the semiconductor laserdiode.

[0078] The shot duration of the laser beam can be controlled in terms ofthe rotation angle of the rotary radiation control.

[0079] In addition to the controlling of the power output of the laser,the energy density can be finely controlled in terms of the duration ofbeam radiation. This arrangement facilitates the sophisticated controlof the laser output to meet a variety of beauty treatments as required.

[0080] The use of the rotary radiation control facilitates thecontrolling of the radiation of the laser beam.

1. A laser beam irradiation device comprising: a semiconductor laserdiode for producing a laser beam; a switching means for changing thesemiconductor laser diode in operation from one to another outputtingstate or vice versa; and a control circuit for controlling the amount ofworking current flowing in the semiconductor laser diode to adjustoutput power of the laser beam by using the switching means for anappropriate performance of either non-thermal or photothermaltreatments.
 2. A laser beam irradiation device according to claim 1wherein the switching means is adapted to change the semiconductor laserdiode between high-outputting state and low-outputting state.
 3. A laserbeam irradiation device according to claim 1 wherein the control circuitfunctions to make the working electric current flows and stops in thesemiconductor laser diode at regular intervals, thereby projecting thelaser beam intermittently.
 4. A laser beam irradiation device accordingto claim 3 wherein one shot of the intermittent radiation is controlledin terms of rotation angle of a rotary control.